A PUBLICATION OF THE ADULT CONGENITAL ASSOCIATION

www.achaheart.org • (888) 9 21-ACHA

ACHA Q and A: Transposition of the Great Arteries after Mustard/Senning Repair What is Transposition of the Great Arteries? What kind of long-term problems do people with In transposition of the great arteries (TGA), the heart’s a Mustard or Senning repair experience? two major arteries are reversed. The blue There are three kinds of problems that people with a entering the heart gets pumped directly out to the Mustard or Senning repair face: rhythm problems, body without going through the . Blood coming baffle problems, and pump problems: from the lungs gets sent back to the lungs rather than • Rhythm problems: Many TGA patients have inborn out to the body. Babies born with TGA will die unless problems with the heart’s electrical system. The there is a hole between the two sides of the heart to scarring from previous can also cause allow some red blood to get out to the body. Many electrical problems. Sometimes the heart’s “relay people with TGA are born with a ventricular septal box,” called the sinus node, is damaged. This can defect (VSD) that allows this to happen. In others, cause sick sinus syndrome, which makes the heart doctors make a hole to keep them alive. Babies born beat too slowly. Pacemakers are used to treat a with TGA almost always need surgery to help the heart too-slow heart. Up to 25% of Mustard/Senning work more normally. Two of these are the patients have a pacemaker by adulthood. Other Mustard and the Senning repair (also called Mustard TGA patients experience heart rates that are too fast or Senning procedures). The main other surgeries are (tachycardia). This happens when a section of the the arterial switch and . heart’s electrical system starts firing too quickly. What is a Mustard or Senning repair? Heart rhythm doctors now often use ablation to treat The Mustard and Senning repair are two similar too-fast heart rates. The doctor first identifies the operations for TGA. Each is named for the surgeon area of the heart that is misfiring. Then, this area is who first performed the operation. In both, the scarred to stop the fast heart rate. If the ablation is surgeon creates a two-way baffle in the top part of the heart. This baffle serves as a bridge between the In this illustration of a heart with TGA that has had a Mustard/ two sides of the heart. In a , the Senning repair, the blue blood flows through the two-way Systemic surgeon uses the patient’s own tissue to create the Venous Baffle (SVB) to the left . The blue blood is pumped baffle. In the , a synthetic material to the lungs to get oxygen. The red oxygenated blood is directed through the Pulmonary Venous (PV) baffle to the right and is used. Both are called “atrial switch procedures” gets pumped by the right ventricle to the rest of the body. because there is a baffle through the heart’s top part, or atria, which allows the blood to reach the ventricles. When and where were Mustard and Senning repairs first done? Dr. Ake Senning of Sweden performed the first Senning procedure in 1957. Dr. William Mustard, from Canada, performed the first Mustard procedure in 1963. In general, the Senning was more common in Europe and the Mustard was more common in the United States and Canada. Are the Mustard and Senning repairs still used? Today’s children born with TGA usually have an operation called an arterial switch. This operation KEY: was first developed in the late 1980s. In the arterial SVC – switch, the surgeon disconnects and reattaches the IVC – Inferior Vena Cava heart’s arteries to create more normal blood flow. SVB – Systemic Venous Baffle PV – Pulmonary Venous Baffle LV – Left Ventricle RV – Right Ventricle This means that Mustard and Senning patients are MPA – Main Ao – usually between 22 and 50 years old. Image courtesy of the Columbus Ohio Adult Congenital Heart Disease Program at ©The Adult Congenital Heart Association. Nationwide Childrenʼs Hospital Heart Center, Columbus, Ohio. successful, further treatment may not be necessary. that might be making your heart struggle. If these Medication can also be used to treat heart rhythm problems can be solved, heart failure may improve. problems. If the problem is life-threatening, a If other treatment options are not working, surgical defibrillator might be implanted. A defibrillator is a options may be considered. In a small number of adult device that shocks the heart into a regular rhythm. TGA patients, switch conversion might be discussed. • Baffle problems: Over time the baffles in the This means that the Mustard/Senning repair is taken Mustard/Senning repair can develop problems. down and replaced with an arterial switch. There are Sometimes they become too narrow (stenotic). ACHD many challenges to successful switch conversions in doctors often can treat a narrowed baffle non- adults. It is highly complex, risky surgery. Switch surgically. They use a tube into the heart (catheter) conversions are rarely done in adults. It should only to place a wire tube, called a stent, in the narrow be done at highly-specialized ACHD centers. If heart area. If a stent cannot fix the problem, surgery may failure worsens and other treatment options are not be needed. Baffles can also leak over time. The baffle available, can be considered. sutures may come loose and holes can develop. Is pregnancy safe for TGA post-Mustard/Senning Sometimes these leaks do not need treatment. If they patients? are large, they can cause problems with blood clots All women with TGA should consult with an ACHD and strokes. Doctors often can use a covered stent to program before getting pregnant. This will help identify stop blood leaks in the baffle. It is important that TGA any heart problems that should be addressed before patients have adult congenital heart disease (ACHD) pregnancy occurs. Most women with TGA post- doctors check their heart regularly to make sure that Mustard/Senning can safely undergo pregnancy and their baffles still work well. delivery. The exceptions are when there is heart • Pump problems: In a normal heart, the left ventricle failure, problems with pressure, and/or pumps blood out to the body. It has thick walls and uncontrolled rhythm problems. All pregnant women strong valves designed to do the hard work of pump- with TGA should be followed by a special maternal ing to the body. The right ventricle has weaker valves fetal health team working together with their ACHD and thinner walls built to pump to the lungs. After a team. In a small number of cases, women with TGA Mustard or Senning repair, the weaker right ventricle experience new problems with heart failure and/or pumps the blood to the body. Over time, the right heart rhythm during pregnancy. These issues may ventricle sometimes has a hard time providing enough continue even after the pregnancy. pump strength to serve the body. When the heart What kind of care is recommended for struggles to keep up with the body’s needs, doctors adults with TGA post-Mustard/Senning? call it heart failure. Heart failure symptoms can include The American College of Cardiology and the American feeling extra-tired on exertion, shortness of breath on Heart Association classify transposition of the great exertion, and/or retaining fluid. Heart failure does not arteries as a highly complex heart defect. This means mean that the heart stops or fails. Research reports that experts recommend that you get care for your that about 10% of TGA post-Mustard/Senning heart at a special ACHD center. You can find a listing patients are now experiencing heart failure. of ACHD clinics at www.achaheart.org. If you have How are pump problems diagnosed? TGA post-Mustard/Senning, you should see your Echo or MRI can be used to estimate the heart’s cardiologist regularly, even if you feel fine. This way pumping strength. Because people with TGA post- you can catch any problems before they start, since Mustard have such unusual anatomy, measuring new heart problems can develop without symptoms. heart function can be challenging. If you have TGA, Many treatments that can help strengthen and protect it is important that your testing be done by an expert your heart work best if started early. in ACHD. Because non-ACHD experts are not The good news is that most people with TGA post- trained in CHD , tests done on TGA patients Mustard/Senning are continuing to do well. By taking at non-ACHD centers can often be inaccurate. good care of your heart and getting recommended How are pump problems treated? care, you can help ensure that you and your heart The good news is that there are many ways that pump continue to thrive. problems in Mustard/Senning patients can be treated and improved. Your ACHD team may recommend Dr. Gary Webb , who provided his expertise for this handout and exercise to strengthen and improve your heart’s pump. accompanying ACHA webinar, directs the ACHD program at There are many medications that also help the heart Cincinnati Children’s Hospital. He previously worked in Toronto, pump more efficiently. Your ACHD team will also where he directed the world’s oldest and largest ACHD program. assess whether there are rhythm or baffle problems He has had the pleasure of working with ACHA on many initiatives and served as chair of the Medical Advisory Board from 2006-2011. ©The Adult Congenital Heart Association.